Clean Room - A compendium according to approved guidelines.

CleanRoom :
A Compendium According to the Approved
Guidelines.
Md. Mosaruf Hossan,
Assistant Production Manager.

References
• ISO 14644
• Part 1: Classification of air cleanliness
• Part 2: Continued compliance with
• Part 3: Metrology and test methods
• Part 4: Design, construction and start-up
• WHO Technical Report Series, No. 902, 2002
• Annex 6: Good manufacturing practices for sterile pharmaceutical
products
• WHO Technical Report Series, No. 961, 2011
• Annex 5: WHO guidelines on good manufacturing practices for
heating, ventilation and air-conditioning systems for non-sterile
pharmaceutical dosage forms
• Annex 6: WHO good manufacturing practices for sterile
pharmaceutical products
• PIC/S GMP Guide (Part I: Basic Requirements For Medicinal Products)
• PIC/S Guide To Good Manufacturing Practice For Medicinal Products -
Annexes
1.ISO 14644
2.WHO Technical Report
3.PIC/S
( Pharmaceutical Inspection Co-
operation Scheme )

Scope
What will be
covered during
this
presentation
A. A Brief review on cleanroom
classification.
B. Introduction of Design Concepts and
Considerations based on ISO 14644 Series
Standards, PIC/S and WHO Guidelines.
C.Testing Methods and Procedures.

Definition
According to Three
Approved Guidelines :

History of Clean
Room
Scientific Basis of
Clean Room

Purposes
Cleanrooms provide for
the control of airborne
contamination to levels
appropriate for
accomplishing
contamination-
sensitive activities.
Area Covered :
1. Aerospace,
2. Microelectronics,
3. Pharmaceuticals,
4. Medical devices,
5. Healthcare (Hospitals)
6. Food.

Purposes
Three Main
Purposes are :
1. The concentration of airborne
particles is controlled.
2. Constructed and used in a manner to
minimize the introduction,
generation, and retention of particles
inside the room
3. Other parameters (Temperature,
Humidity, and Pressure) are
controlled

Classification
Occupancy states:
1. As-built:
Installation is complete, all services functioning,
no production equipment, materials, or
personnel present
2.At-rest:
No personnel present
3. Operational:
The installation is functioning in the specified
manner, specified number of personnel present
and working.
level of airborne particulate
cleanliness,
represents maximum
allowable concentrations
(in particles per cubic
metre of air) for considered
sizes of particles.

Classification
The maximum permitted concentration of particles, Cn, for each
considered particle size, D,
where:
Cn represents the maximum permitted concentration ( in
particles/m^3 of air ) of airborne particles that are equal to or
larger than the considered particle size. Cn is rounded to the
nearest whole number.
N is the ISO classification number, which shall not exceed the
value of 9. Intermediate ISO classification numbers may be
specified, with 0.1 the smallest permitted increment of N.
D is the considered particle size in m m.
0.1 is a constant with a dimension of m m.
The particulate cleanliness
of air shall be defined in
one or more of three
occupancy states, viz. “as-
built”, “at-rest”, or
“operational”.

Classification
1. ISO CLASSIFICATION NO
2. US FEDERAL STANDARD 209E
3. EUROPEAN ECONOMIC COMMUNITY
CLEANROOM
CLASSIFICATION
BASED ON

Classification
1. ISO CLASSIFICATION
NO

Classification
Graphical representation
of ISO-class concentration
limits for selected ISO
classes

Classification
2. US FEDERAL
STANDARD 209E
This standard was first published in
1963 in the USA and titled "Cleanroom
and Work Station Requirements,
Controlled Environments". It was
revised in 1966 (209A), 1973 (209B),
1987 (C), 1988 (D) and 1992 (E)
CLASS LIMITS : 0.5 MICRON
Class CLASS LIMIT
ISO SI ENGLISH CUBIC FOOT
CUBIC
METER
6 M 3.5 100 100 3530
7 M 4.5 1000 1000 35300
8 M 5.5 10000 10000 353000
9 M 6.5 100000 100000 3530000

Classification
2. US FEDERAL
STANDARD 209E
CLASS LIMITS : 5 MICRON
Class CLASS LIMIT
ISO SI ENGLISH CUBIC FOOT
CUBIC
METER
6 M 3.5 100
7 M 4.5 1000 7 247
8 M 5.5 10000 70 2470
9 M 6.5 100000 700 24700

Classification
3. EUROPEAN ECONOMIC
COMMUNITY
(WHO Technical Report Series,
No. 902, 2002 Annex 6 )
CLASS LIMITS : 0.5 MICRON
Grade MAX. PERMITTED NO OF PARTICLES PER CUBIC
METER EQUAL TO OR ABOVE 0.5 MICRON
At Rest In Operation
A 3520 3520
B 3520 3520 X 100
C 3520 X 100 3520 X 1000
D 3520 X 1000 Not Defined

Classification
3. EUROPEAN ECONOMIC
COMMUNITY
CLASS LIMITS : 5 MICRON
Grade MAX. PERMITTED NO OF PARTICLES PER CUBIC
METER EQUAL TO OR ABOVE 0.5 MICRON
At Rest In Operation
A 20 20
B 29 2900
C 2900 29000
D 29000 Not Defined

Classification :
Summary
Comparison of Different
Airborne Particulate
Classification System for Clean
Areas.
(This comparison is defined
based on at-rest limitations )

Classification :
Microbiological
Limits
Refference : PIC/S Guide To
GMP For Medicinal Products
Annex 1

Particles
Simply stated, airborne
particles are solids
suspended in the air, falls
within a threshold size in
the range from 0.1 to 5µm.
Since many of these air borne contaminants are
harmful to products and people, their removal is
necessary on medical, legal, social or financial
grounds.
Air, whether it is from outside or re-circulated,
acts as a vehicle for bacterial and gaseous
contaminants brought in by the movement of
people, material, etc.

Particles
There are two main
sources of particulates :
1. External Sources and
2. Internal sources.
1. Outside make-up air introduced into the
room: this is typically the largest source of
external particulates
2. Infiltration through doors, windows and
other penetration through the cleanroom
barriers
1. EXTERNAL SOURCES

Particles
Control Action
1. Make-up air filtration
2. Room pressurization
3. Sealing of all penetrations into the space
1. EXTERNAL SOURCES

Particles
There are two main
sources of particulates :
1. External Sources and
2. Internal sources.
1. People in the clean area: people are
potentially the largest source of internally
generated particulates
2. Cleanroom surface shedding
3. Process equipment
4. Material ingress
5. Manufacturing processes
2. INTERNAL SOURCES

Particles
Control Action
1. Design airflow path to shield humans
from surroundings
2. Use of air showers [to continually wash
occupants with clean air]
3. Using hard-surfaced, non-porous materials
such as polyvinyl panels, epoxy painted walls,
and glass board ceilings
4. Proper gowning procedures, head wear
1. INTERNAL SOURCES

Microbial Limit
Recommended Limit for
Microbial Contamination
(Ref. : PIC/S Guide To GMP For
Medicinal Products Annex 1)

Airborne particle
physical control
1.Filtration (HEPA)
2.Dilution
(Higher Air change Rate)
3.Isolation
1.Filtration (HEPA)

Airborne particle
physical control
1.Filtration (HEPA)
2.Dilution
3.Isolation
2.Dilution

Airborne particle
physical control
Calculation of ACH
STEP-1 : Velocity of Air Flow below the HEPA Filter in ft/min.
( V1+V2+V3+V4+V5 )
V =
5
ft/min.
Average Velocity from diffeent Point of HEPA Filter.
STEP-2 : Area of the filter
A = Length X Width ( Sq. Ft )
STEP-3 : Total Air volume Per Minute Supplied in Room.
T = V ( Step-1 ) X A ( Step-2 )
STEP-4 : Total Air in the Room.
Volume = Length X Width X Height ( Cube ft )
STEP-5 : Air han Change Rate per Hour
ACH = T/VOLUME X 60
V1
V
5
V
3
V
2
V
4

Airborne particle
physical control
1.Filtration (HEPA)
2.Dilution
3.Isolation
3. Isolation
HEPA class retention (total) retention (local)
E10 > 85% ---
E11 > 95% ---
E12 > 99.5% ---
H13 > 99.95% > 99.75%
H14 > 99.995% > 99.975%
U15 > 99.9995% > 99.9975%
U16 > 99.99995% > 99.99975%
U17 > 99.999995% > 99.9999%

Selective Area According
to CleanRoom
Classification :
PIC/S
( Pharmaceutical
Inspection Co-
operation Scheme )
• Grade A: The local zone for high risk operations:
• Filling zone, open ampoules and vials, making aseptic
connections.
• Provided by a LAF work station with a homogeneous air speed in
a range of 0.36 – 0.54 m/s (guidance value)
• A unidirectional air flow and lower velocities may be used in
closed isolators and glove boxes.
• Grade B: For aseptic preparation and filling, this is the
background environment for the grade A zone.
• Grade C and D: Clean areas for carrying out less critical
stages in the manufacture of sterile products.

PIC/S General
Paragraphs
• Clean Areas:
• Entry through airlocks for personnel and/or for equipment and
materials.
• Supplied with air has passed through filters of an appropriate
efficiency.
• The various operations of component preparation, product
preparation and filling  in separate areas within the clean area
• Manufacturing operations:
• Product is terminally sterilized. ( A process whereby a product is
sterilized in its final container or packaging, which permits the
measurement and evaluation of quantifiable microbial lethality. In
principle, the SAL should be less than 10-6.)
• Conducted aseptically at some or all stages.
• In order to meet “in operation” conditions, areas should be
designed to reach certain air-cleanliness levels in the “at rest”
occupancy state.

PIC/S General
Paragraphs
• “In operation” classification may be demonstrated
during normal operations, simulated operations or
during media fills (worst-case)
• Clean rooms and clean air devices should be routinely
monitored
• Monitoring locations based on risk analysis and the results
of classification
• Grade A: full duration of critical processing
• Grade A: Such a frequency and sample size that all
interventions, transient events is captured and alarms
triggered
• Grade B: The same as grade A; the sample frequency may
be decreased.
• Grade C and D: in accordance with the principles of
quality risk management.

PIC/S General
Paragraphs
• Terminally Sterilized Products
• Preparation of components and most products
should be done in at least a grade D environment
• Where the product is at a high or unusual risk
of microbial contamination  Grade C
• Filling of products for terminal sterilization 
Grade C
• Where the product is at unusual risk of
contamination from the environment,
filling  Grade A with Grade C background.
• Preparation and filling of ointments, creams,
suspensions and emulsions should  grade C
before terminal sterilization

PIC/S General
Paragraphs
• Aseptic Preparation
• Components after washing  Grade D
• Handling of sterile starting materials, unless
subjected to sterilization or filtration  Grade A
with Grade B background.
• Otherwise  Grade C
• Handling and filling of aseptically prepared products
 Grade A
• Transfer of partially closed containers, as used in
freeze drying,
 either in a Grade A environment with grade B
background or in sealed transfer trays in a grade B
environment

PIC/S Paragraphs
on Premises
• All exposed surfaces should be smooth, impervious
and unbroken
• To reduce accumulation of dust and to facilitate
cleaning there should be no unclean able recesses
and a minimum of projecting ledges, shelves,
cupboards and equipment.
• False ceilings should be sealed.
• Sinks and drains should be prohibited in grade A/B
areas
• Changing rooms should be designed as airlocks, The
final stage of the changing room should, in the at-
rest state, be the same grade as the area into which it
leads.

PIC/S Paragraphs
on Premises
• Both airlock doors should not be opened simultaneously;
interlocking system or a visual and/or audible warning
system should be operated.
• A filtered air supply should maintain a positive pressure and
an air flow relative to surrounding areas of a lower grade. a
pressure differential of 10-15 pascals
• It should be demonstrated that air-flow patterns do not
present a contamination risk.
• A warning system should be provided to indicate failure in
the air supply.

PIC/S Paragraphs
on Premises
Airlock : Airlock helps to
protect Classified area from
the contamination that may
occurs during entry and exit
of personnel & Materials
.Airlock is called as PAL (
Personnel Airlock ) & MAL
( Material Airlock )
Type :
A. Cascade Airlock : Higher Pressure is one side & Lower pressure is
another side.
Prevent to enter dust & Contaminants from outside
to airlock and from airlock to inner side.
B. Bubble Airlock : Higher pressure inside the Airlock and Lower
Pressure in both out side.
Prevents the flow of air between two areas through
the airlock by creating a pressure barrier.
C. Sink Airlock : Lower Pressure inside the airlock & Higher Pressure
in both the outside.
This airlock Pulls air from both adjacent area by
creating a low pressure barrier.

PIC/S Paragraphs on
Premises
Type of Airlock

Planning &
Designing
• A project plan shall be developed to define the
requirements of the products, the processes and the scope
of the installation.
• A process equipment list shall be compiled, and shall
include the critical requirements for each piece of process
equipment.
• Diversity factors shall be defined, considering peak and
average demand for each utility and environmental control
system.
• A contamination control concept shall be developed for
each zone of an installation.

Design: Control
and segregation
concepts • For economic, technical and operational reasons,
clean zones are often enclosed or surrounded by
further zones of lower cleanliness.
• The zones with the highest cleanliness demands is
reduced to the minimum size.
• Movement of material and personnel between
adjacent clean zones gives rise to the risk of
contamination transfer,
 management of material and personnel flow

Design: Control
and segregation
concepts
Shell-Like Containment Control
Concept : External Contaminants
should be removed by effective
Filtration of the supply air .

Design: Personnel
flow and Material flow
• Personnel flows considered:
• Manufacturing personnel
• Maintenance personnel
• Quality control personnel
• Material flows considered:
• Raw materials
• Finished goods
• Waste
• Product (In-process, Intermediate & Final)
• Equipment
• Clean and dirty components
• Portable equipment
• Product containers

Design: Personnel flow
and Material flow

Design: Air Flow Patterns
Air flow patterns:
Clean room airflow patterns can be
categorized as either unidirectional
or non-unidirectional (or mixed).
Unidirectional airflow:
-ISO Class 5 and cleaner
-May be either vertical or horizontal
-Airflow rely upon a final filtered air supply and
-Return inlets are nearly opposite air supplies to
maintain the airstream straight

Air flow patterns:
Clean room airflow patterns
can be categorized as either
unidirectional or non-
unidirectional (or mixed).

Unidirectional Air flow

- Horizontal Air Flow
- Vertical Air Flow

- Vertical Air Flow
The Position in which the operator stands relative to the
source of Dust liberation and Air flow should be determined
to ensure that the operators is not in the path of an airflow
that could lead to contamination of the product. ( Working
Document QAS/15.639 ).

Situation where an open bin is placed below a
vertical Unidirectional flow distributor. The
downward airflow should be prevented from
entering the bin , and then being forced to rise
again, as this would carry light dust up toward’s the
operators face . So, in this case a partial cover is
need to add over the bin to limit the entry of air .(
Working Document QAS/15.639 ).
- Vertical Air Flow

Air flow patterns:
Cleanroom airflow patterns
can be categorized as either
Non-Unidirectional
airflow:
-Air flow outlets located in
multiple positions. Filter
outlets may be distributed at
equal intervals or grouped over
the core process.
The final filter location may be
remote, (avoid contamination
ingress between filters and
cleanroom)
Return air locations in non-
unidirectional airflows are not
as critical
Distribute the returns to
minimize dead zones within
the cleanroom

Air flow patterns:
Cleanroom airflow patterns can
be categorized as either

Disturbance of
unidirectional airflow

Contamination Control
Concepts
1. Product Protection
2. Personnel/Environmental
Protection
3. Personnel/Product/
Environmental Protection

Design: Segregation
Concepts
1. Displacement concept :
(low pressure differential, high airflow)
-by means of a low turbulent "displacement" airflow, >0,2 m/s.
2. Pressure differential concept :
(high pressure differential, lo.w airflow)
-The pressure differential in the range of
5 - 20 Pa, to allow doors to be opened
and to avoid unintended turbulence.
3. Physical barrier concept
-Use of an impervious barrier to prevent contamination transfer to a clean
zone from a less clean zone.
In order to protect clean
rooms from
contamination from
adjacent less clean
spaces:

Design: Layout of an
installation
General
Considerations:
• Size: of cleanroom should be minimum. if a large space
is required, it should be divided, with or without physical
barriers.
• Workstation siting and organization: critical
workstations away from, major traffic pathways.
less clean operations site downstream of cleaner
operations.
• Ancillary areas and adjacent cleanrooms:
• Pressure or flow differentials,
• Access and communication arrangements
(such as airlocks, speech panels and intercoms
cross-contamination from less
clean zones does not compromise
the cleaner zones.

installation
General Considerations
( Contd ):
• Utility services and ancillary equipment
• General: Utility services should be designed and installed
such that the cleanroom is not compromised by
contamination.
• exposed piping, tubing and cable runs should be
minimized,
• Vacuum-cleaning equipment
• Sprinkler systems (A fire sprinkler system is an active fire protection method,
consisting of a water supply system, providing adequate pressure and flow rate to a water
distribution piping system, onto which fire sprinklers are connected. )
• Communication systems: to reduce personnel movement
• Glazing: Avoid heat loss and solar gain, non-opening
double glaze

installation
( Contd ):

installation
( Contd ):
• Access (contd.)
• Changing rooms: Have three functional zones:
• Entry: access from ancillary. appropriate for removal, storage,
disposal and/or redonnning of garments not permitted within
the cleanroom;
• Transition zone: where garments or personal equipment
dedicated to the cleanroom are stored, donned or removed.
• Inspection/access zone: where inspection of the completed
gowning is accomplished and provides access to cleanroom.
• The three functional zones may be separated by a physical
barrier (e.g. a stepover bench or airlock)

installation
( Contd ):
• The following requirements should be defined:
• number of people passing through the gowning procedure
• the gowning procedure (i.e. what garments are to be taken off
and put on)
• the frequency of garment replacement.
• Consideration should be given to the following provisions:
• Storage and disposal of garments;
• Storage before use and disposal of consumable items
• Storage of personal items;
• Hand-washing and drying or other decontamination processes;
• Display or posting of gowning sequence, with clear instructions;
• full-length mirrors to check effective fit.

Design: Construction and
materials
• The materials used should be selected to meet the
requirements of the installation, and should take
into account the following:
a) the cleanliness class;
b) effects of abrasion and impact;
c) cleaning and disinfection methods and
frequencies;
d) chemical/microbiological attack and corrosion.
• Surface cleanliness and cleanability of materials of
construction
• Fittings in airlocks: Minimum horizontal surfaces

materials
• Ceilings: Ceilings should be sealed, penetration points should
be kept minimum.
• Walls: Materials and surface finishes should meet all general
requirements.
•Particular considera tión to impact and abrasion. (rubbing strips,
protective bars)
•Cover strips or seals between panels should be smooth, with
rounded edges
•Use double glazing, with airtight seal, which can enable flush
mounting
•Doors should present as few horizontal surfaces as possible,
thresholds avoided.
•Consider use of push plates, automatic openings, or appropriate
door-swing
• Floors: Floors or floor coverings should be non-porous, slip-
resistant, abrasion-resistant, conductive if necessary.

materials

Design: Control of air
Cleanliness
1. Air filtration systems
• Air filtration systems including filter elements,
mounting frames, housings, gaskets, sealants and
clamping systems should be selected to suit both the
cleanliness and using condition.
• Three basic stages of air filtration are recommended:
• prefiltering of the outside air to ensure adequate
quality of air supply
• secondary filtering in the air conditioning plant to
protect the final filters;
• final filtering before cleanroom supply.
• “Sacrificial" filters or temporary filters: considered to
protect the air cleanliness of air-handling systems
during construction and commissioning.

Design: Control of air
Cleanliness

HVAC Systems
( Standard Layout )

HVAC Systems
( Conventional Layout )

HVAC Systems
( Diffusers )
Definition & Types
Air diffusers are used in clean rooms and other controlled
areas to distribute the clean air passed through the HEPA
filters. Diffusers are important part of the HVAC system and
play vital role in maintenance of classified area.
Number of diffusers in a room depends upon the volume
of the area, size of diffusers and required air changes par
hour. Diffusers are mounted in the ceiling of the room to
distribute the uniform air in the area and return risers
should not be near the diffusers. Otherwise air pockets will
form that can increase the contamination level in the area.
Place and type of diffusers to be used should be included
in the HVAC system qualification.
Generally two types of air diffusers are used in
pharmaceutical industries.
1. Induction Diffusers
2. Perforated Plate Diffusers
3. Swirl Diffusers

HVAC Systems
( Diffusers )
1. Induction Diffuser
Induction diffusers are generally used in offices and
therefore also called office type diffusers.
These diffusers direct the air to flow in different directions.
WHO does not recommend these types of diffusers to use
in pharmaceutical processing areas because these diffusers
mix the fresh air with the contaminated room air (see
figure) and the air should be replaced with the fresh air to
minimize the contamination.
In the areas where dust is liberated it is important to
replace the air containing dust with the fresh air.

HVAC Systems
( Diffusers )
2. Perforated Plate Diffusers:
These are the WHO recommended and widely used diffusers
in pharmaceutical industries. They allow the air to flow in
all directions replacing the air containing dust and
contamination with the fresh air from supply.

HVAC Systems
( Diffusers )
3. Swirl Diffusers:
These rotating diffusers are also recommended by the WHO
which rotates during the fresh air supply allow distributing
the fresh air throughout the area.

Tests Methods
Cleanroom tests:
1.Required Test
2.Optional Test
• Required Tests: An airborne particle count test shall
be carried out in order to classify an installation
• Optional Tests:
• Airborne particle count for ultrafine and/or
Micro-particles
• Airflow test
• Air pressure difference tests
• Installed filter system leakage test
• Air flow direction tests and visualization
• Temperature, Humidity and Electrostatic tests
• Particle deposition tests
• Recovery tests
• Containment leak tests

Required Tests
Airborne particle count for
classification and test
measurement:
1.Measurement of airborne particle concentrations with size 0.1
- 5 μm.
2.A discrete-particle-counting, light-scattering instrument is used
to determine the concentration of airborne particles.
3.Prior to testing, verify that all aspects of the cleanroom and
functioning in accordance with specifications.
-Airflow rate or velocity tests;
-Pressure difference test;
-Containment leakage test;
-Filter leakage test.

Required Tests
classification and test
measurement:
Sampling
- Minimum number of sampling point locations:
-Sampling locations evenly distributed, at the height of the work activity.
-Sample a sufficient volume of air that a minimum of 20 particles would
be detected if the particle concentration for the largest considered
particle size were at the class limit for the designated ISO class.
-The volume sampled at each location shall be at least 2 litres, with a
minimum sampling time at each location of 1 min.
-Compute the overall mean of the averages, standard deviation, and 95%
upper confidence limit from the average particle concentrations for all
locations.

Optional Tests
ultrafine and/or Micro-particles
Airborne particle count for ultrafine particles
-Smaller than 0,1μm
-DPC, with a capability for accurate particle size definition
up to at least 1μm.
-Condensation nucleus counter (CNC)
-Small sampling flow & long sampling tube  diffusion
loss.
Airborne particle count for macro-particles
-Larger than 5 μm.
-There are two general categories of macroparticle
measurement methods.
= collection by filtration or inertial effects, followed
by microscopic measurement
= in situ measurement of the concentration and size
of macroparticles with a time-of-flight particle
counter or DPC

Optional Tests
ultrafine and/or Micro-particles
Two general categories of macroparticle measurement methods:
A. collection by filtration or inertial effects, followed by microscopic
measurement of the number and size, or measurement of the mass of
collected particles:
-filter collection and microscopic measurement will report
macroparticles using particle size based upon the agreed
diameter;
-cascade impactor collection and microscopic measurement will
report macroparticles using particle size based upon the
microscopist's choice of reported particle diameter;
-cascade impactor collection and weight measurement will
report macroparticles using particle size based upon an
aerodynamic diameter;
B. In situ measurement of the concentration and size of
macroparticles with a time-of-flight particle counter or a DPC:
-DPC measurement of particle size based upon an equivalent
optical diameter;
-Time-of-flight particle size measurement based upon an
aerodynamic diameter.

Optional Tests
Airflow Test
Airflow Test
• To measure airflow velocity and uniformity, and supply airflow rate
• Measurement of velocity distribution is necessary in unidirectional
airflow cleanrooms, and supply airflow rate in non-unidirectional
cleanrooms.
• Supply airflow rate (air volume supplied to the clean installation per
unit of time) can also be used to determine the air changes.
• Airflow rate is measured either downstream of final filters or in air
supply ducts; both methods rely upon measurement of velocity of
air passing through a known area.

Optional Tests
Airflow Test
Procedure for unidirectional airflow installation test
• Supply airflow velocity
• Measured at approximately 150-300 mm from the filter face.
• Number of measuring points should be the square root of 10
times of area in m2 but no less than 4. At least 1 point for each
filter outlet
• Uniformity of velocity within the cleanroom
• measured at approximately 150-300 mm from the filter face and
the subdivision into grid cells should be defined
• Supply airflow rate measured by filter face velocity
• The results of the airflow velocity test can be used to calculate
the total supply airflow rate.
• Supply airflow rate in air ducts
• by volumetric flowmeters (orifice meters, Venturi meters and
anemometers)

Optional Tests
Airflow Test
Procedure for non-unidirectional airflow
installation test
• Air volume supply rate and air-change rate are the
most important parameters.
• Supply airflow rate measured at the inlet
• Because of local turbulence, use of a flowhood that
captures all of the air issuing from each supply
diffuser is recommended.
• Supply airflow rate calculated from filter face
velocity
• Evaluation of the supply airflow rate without a
flowhood may be done with an anemometer
downstream of each final filter. The supply airflow
rate is determined from the airflow velocity multiplied
by the area of exit.

Optional Tests
Air Pressure Difference
Test
• Verify the capability of the complete installation to maintain the
specified pressure difference between separate spaces
• With all doors closed, the pressure difference between the
cleanroom and any surrounding should be measured and
recorded.
• The following should be considered:
• installation of permanent measuring points;
• take measurements near the middle of the cleanroom
away from any supply air inlets or return air outlet.

Optional Tests
Installed filter system
leakage test
Installed filter system leakage test
• To confirm that the filter system is properly
installed and that leaks have not developed
• Introducing an aerosol challenge upstream of the
filters and scanning immediately downstream of
the filters and support frame or by sampling in a
downstream duct.
• Applied to cleanrooms in “as-built” or in “at-rest”
occupational states, and when commissioning new
cleanrooms, or existing installations require re-
testing, or after the final filters have been replaced
• Detection of leakage by Scanning / Stationary
remeasuring

Optional Tests
Apparatus and materials
for installed filter system
leakage tests
-Aerosol photometer
-Discrete-particle counter (DPC)
-Suitable pneumatic or thermal aerosol
generator(s)
-Suitable aerosol dilution system.
-Suitable aerosol source substances

Optional Tests
Airflow direction test and
visualization
• To confirm that the airflow direction and its
uniformity conform to the design and performance
specifications
• can be performed by the following four methods:
1. Tracer thread method;
silk threads, single nylon fibers, flags or thin film
tapes and effective lighting
2. Tracer injection method;
tracer particles illuminated by high intensity light
sources (DI Water , alcohol/glycol)
3. Airflow visualization method by image processing
techniques; (Quantitative)
4. Airflow visualization method by the measurement
of velocity distribution.

Optional Tests
Airflow direction test and
visualization

Optional Tests
Temperature Test
• Capability to maintain the air temperature level within
the control
• Measured at a minimum of one location for each
temperature-controlled zone.
• Measurement time should be at least 5 min with one
value recorded at least every minute.
• Comprehensive temperature test:
• At least 1 h after the air-conditioning system has been
operated
• The number of measuring locations should be at least
two.
• Probe should be positioned at work-level height and at
a distance of no less than 300 mm from the ceiling,
walls, or floor of the installation

Optional Tests
RH Test
• Capability to maintain the air humidity level
• Expressed as relative humidity or dew point
• The sensor should be located at least at one location
for each humidity control zone, and sufficient time
should be allowed for the sensor to stabilize.
• The measurement time should be at least 5 min.

Optional Tests
Particle Deposition Test
• Sizing and counting particles that can be deposited
from the air onto product or work surfaces in the
installation.
• Particles are collected on witness plates with surface
characteristics similar to those of the at-risk surface
• Are sized and counted using optical microscopes,
electron microscopes, or surface scanning apparatus.
• The witness plate should be placed in the same plane
as the at-risk surface. And at the same electrical
potential as the test surface.
Measuring Device :
Witness plate material: micro-porous membrane filters, double-
sided adhesive tape, Petri dishes Petri dishes containing a
contrasting colour (black) polymer, such as polyester resin;
photographic film (sheet), microscope slides (plain or with
evaporated metal film coating), glass or metal mirror plates;
semiconductor wafer blanks; glass photo mask substrates

Optional Tests
Recovery Test
• Ability of the installation to eliminate airborne
particles.
• Only important and recommended for non-
unidirectional airflow systems
• This test is not recommended for ISO Classes 8 and
9.
• 100:1 recovery time is defined as the time required
for decreasing the initial concentration by a factor
of 0,01

Optional Tests
Containment leak test
• Determine if there is intrusion of contaminated air
into the clean zones from non-controlled areas
• Particle concentration outside should be greater
than the cleanroom concentration by a factor of
103. If the concentration is less, generate an aerosol.
• To check for leakage through construction joints,
cracks or service conduits, scan inside the enclosure
at a distance of not more than 5 cm from the joint,
at a scan rate of approximately 5 cm/s.

Clean Room - A compendium according to approved guidelines.

Clean Room - A compendium according to approved guidelines.

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